The present invention relates to an improvement in the change-over shutter of a light-wave range finder.
A light-wave range finder measures distance by measuring a phase difference in a manner such that light emitted from a light emitting element such as a light emitting diode (LED) and modulated with a predetermined frequency is emitted towards a reflector such as a corner-cube or the like placed at the position to be measured, the reflected light from the reflector being focussed on a light receiving element, the reflected light then being converted into an electrical signal, to detect the distance by measuring the difference in phase between the phase at modulation and as received.
In the light-wave range finder thus constructed, the measuring error in the distance is important in the performance of the device, this measuring error being produced by electrical and/or optical causes.